VALVULAR • DICTIONARY ONE.COM • Definition of Valvular

... termination of the ileum the 'caecum' makes its appearance, with a kind of valvular opening into it, of such a nature that everything that passes along it having reached the blind or closed end, must return in order to escape; or rather the office of the caecum is to permit certain alimentary ...

— The Dog - A nineteenth-century dog-lovers' manual, - a combination of the essential and the esoteric. • William Youatt

... every natural family, is very unequal, and in some cases seems to be entirely lost." Again, in another work he says, the genera of the Connaraceae "differ in having one or more ovaria, in the existence or absence of albumen, in the imbricate or valvular aestivation. Any one of these characters singly is frequently of more than generic importance, though here even, when all taken together, they appear insufficient to separate Cnestis from Connarus." To give an example among insects: in one great division of the Hymenoptera, ...

— On the Origin of Species - 6th Edition • Charles Darwin